Beta: DO Family

Intergrowth Family Beta

Periodic Building Unit


Periodic Building Unit (PerBU):	beta layer

Layer symmetry	P (-4) m 2

2D cell parameters	a = 12.66 Å	b = 12.66 Å	gamma = 90°

References
	Higgins, J.B., LaPierre, R.B., Schlenker, J.L., Rohrman, A.C., Wood, J.D., Kerr, G.T. and Rohrbaugh, W.J.
		"The framework topology of zeolite beta"
		Zeolites, 8, 446-452 (1988)
	Newsam, J.M., Treacy, M.M.J., Koetsier, W.T. and de Gruyter, C.B.
		"Structural characterization of zeolite beta"
		Proc. R. Soc. Lond. A, 420, 375-405 (1988)

Connectivity pattern

Examples

The layers are stacked along the [001] direction using the following connectivity patterns

Symmetry Operation^*	Translation^*	Comment	Image
m	1/3 a	the next layer cannot be translated along a
m	-1/3 a	the next layer cannot be translated along a
m	1/3 b	the next layer cannot be translated along b
m	-1/3 b	the next layer cannot be translated along b
m	none	connectivity pattern for the next layer changes with each m operation

^* relative to the previous layer

Short explanation:
The "purple layer" is a mirror image of the previous layer (symmetry operation m) and is translated 1/3 of a unit cell along a.
Note: The next layer cannot be translated along the same axis, e.g. a "purple" layer can only be followed by a yellow, blue or green layer.

Detailed Explanation:
Each application of a mirror operation changes the pattern of the connecting T atoms. If they form rows along the a direction on the top surface of the previous layer, only translations of zero (green layer) or ±1/3 a (purple or brown layer) are possible. If they form rows along the b direction (gray spheres), only translations of zero (green layer) or ±1/3 b (yellow or blue layer) are possible. The connecting T atoms (those pointing up) from the top surface of the previous layer (gray layers) are highlighted as spheres in the examples to the right.


Effect on channel system
	The disorder does not block the channel system

Simplest ordered end members

The color of each layer reflects the symmetry/translation operation used to generate it from the previous layer (see table above).


Polymorph Beta_A

Cell Parameters:	tetragonal	P 4₁ 2 2: (# 91)
	a = 12.6614 Å	b = 12.6614 Å	c = 26.4061 Å
	α = 90.0000°	β = 90.0000°	γ = 90.0000°
	Volume =	4233.2 Å³
Framework Density (FD_Si):	15.1

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	6.59 Å
	that can diffuse along	a: 5.94 Å	b: 5.94 Å	c: 5.94 Å
		addional volume data

Composite Building Units:


mor	bea	mtw

Beta_A is chiral and has an enantiomer with the space group 4₃ 2 2
In this space group and setting, the PerBUs are stacked along [001]

	Note: This polymorph has NOT been observed as a pure ordered material


Polymorph Beta_B

Cell Parameters:	monoclinic	C 1 2/c 1: (# 15)
	a = 17.8965 Å	b = 17.9200 Å	c = 14.3282 Å
	α = 90.0000°	β = 114.8030°	γ = 90.0000°
	Volume =	4171.3 Å³
Framework Density (FD_Si):	15.3

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	6.82 Å
	that can diffuse along	a: 5.88 Å	b: 5.88 Å	c: 5.88 Å
		[1 1 0] : 6.23 Å
		addional volume data

Composite Building Units:


mor	bea	mtw

In this space group and setting, the PerBUs are stacked along [001]

	Note: This polymorph has NOT been observed as a pure ordered material


Polymorph Beta_CH

Cell Parameters:	monoclinic	P 1 2/c 1: (# 13)
	a = 12.2815 Å	b = 12.2847 Å	c = 27.4117 Å
	α = 90.0000°	β = 107.2880°	γ = 90.0000°
	Volume =	3948.9 Å³
Framework Density (FD_Si):	16.2

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	6.46 Å
	that can diffuse along	a: 5.3 Å	b: 5.69 Å	c: 5.3 Å
		addional volume data

Composite Building Units:


mor	bea	mtw

In this space group and setting, the PerBUs are stacked along [001]
Beta_CH is an ordered intergrowth of Beta_A and Beta_B

	Note: This polymorph has NOT been observed as a pure ordered material


Polymorph BEC

Cell Parameters:	tetragonal	P 4₂/m m c: (# 131)
	a = 12.7690 Å	b = 12.7690 Å	c = 12.9770 Å
	α = 90.000°	β = 90.000°	γ = 90.000°
	Volume =	2115.9 Å³
Framework Density (FD_Si):	15.1

	Ring sizes (# T-atoms):	12 6 5 4
	Channel dimensionality:	Topological (pore opening > 6-ring): 3-dimensional

Maximum diameter of a sphere:
	that can be included	6.95 Å
	that can diffuse along	a: 6.09 Å	b: 6.09 Å	c: 6.09 Å
		addional volume data

Composite Building Units:


mor	d4r	mtw

In this space group and setting, the PerBUs are stacked along [001]
Adjacent layers generated by the same connectivity pattern (same basic color) are shown with different shades for clarity

	Note: This polymorph corresponds to the ordered framework BEC

Disorder Example



	There is no blocking of the 3D channel system.